Scleroderma (systemic sclerosis, SSc) is a generalized disorder of small arteries, microvessels and the diffuse connective tissue characterized by scarring (fibrosis) and vascular obliteration of the skin, gastrointestinal tract, lungs, heart, and kidneys in which hidebound skin is the clinical hallmark. Excessive deposition of extracellular matrix most likely results from transcriptional activation of the collagen genes demonstrated directly in scleroderma biopsies by in situ hybridization techniques. Because lesional fibroblasts maintain an activated phenotype during propagation in vitro, we have been able to study the molecular mechanisms responsible for the elevated expression of extracellular matrix genes in these fibroblasts. We have previously established that scleroderma and control fibroblasts respond differently to TGFbeta. TGFbeta stimulates collagen alpha2(I) (COL1A2) transcription in control skin fibroblasts while in SSc fibroblasts transcription of COL1A2 is constitutively elevated and resistant to further stimulation by TGFbeta, suggesting that both intrinsic upregulation of the COL1A2 gene in SSc fibroblasts and TGFbeta mediated stimulation of this gene in normal fibroblasts may involve the same mechanism. Furthermore, our preliminary data indicate that different transcription factors are involved in TGFbeta induction of the COL1A2 gene in human and mouse fibroblasts. To elucidate the mechanisms responsible for altered expression of collagen genes in SSc fibroblasts we propose: 1) to complete identification of human COL1A2 cis-acting regulatory element(s) involved in mediation of TGFbeta stimulation in control fibroblasts and upregulation of expression of this gene in SSc fibroblasts, 2) to cone and characterize the cognate transcription factor(s), and 3) to confirm the role of isolated transcription factor(s) in regulation of COL1A2 expression in control and fibrotic fibroblasts. Completion of the proposed studies will contribute to our understanding of molecular mechanisms responsible for altered behavior of SSc fibroblasts and the pathogenesis of fibrosis.